1. Field of the Invention
The present invention relates to a pneumatic tire suitable as a tire for an iced or snow-covered road, and specifically to a pneumatic tire having snow performances enhanced without sacrificing its running performance exhibited on dry road surfaces.
2. Description of the Related Art
Proposals have been made on a pneumatic tire, as a tire for an iced or snow-covered road, whose tread part includes: multiple main grooves extending in a tire circumferential direction; multiple lateral grooves extending in a tire width direction; and multiple sipes formed in each of land sections into which the tread part is partitioned by the multiple main grooves and the multiple lateral grooves (see Japanese patent application Kokai publication No. Hei. 2008-221955, for instance).
Such a pneumatic tire aims at securing its snow performances on the basis of an edge effect of each of the grooves and sipes. To this end, the grooves and sipes are increased in number, and the total edge length is increased. This makes it possible to enhance the snow performances. However, the increase of the grooves and sipes in number causes a decrease in the total area of the land sections, in turn deteriorating the rigidity of the tread part. As a result, the running performance particularly on dry road surfaces is degraded.